1/* mc68020 __mpn_lshift -- Shift left a low-level natural-number integer. 2 3Copyright (C) 1996, 1998 Free Software Foundation, Inc. 4 5This file is part of the GNU MP Library. 6 7The GNU MP Library is free software; you can redistribute it and/or modify 8it under the terms of the GNU Lesser General Public License as published by 9the Free Software Foundation; either version 2.1 of the License, or (at your 10option) any later version. 11 12The GNU MP Library is distributed in the hope that it will be useful, but 13WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 14or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 15License for more details. 16 17You should have received a copy of the GNU Lesser General Public License 18along with the GNU MP Library; see the file COPYING.LIB. If not, write to 19the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, 20MA 02111-1307, USA. */ 21 22/* 23 INPUT PARAMETERS 24 res_ptr (sp + 4) 25 s_ptr (sp + 8) 26 s_size (sp + 16) 27 cnt (sp + 12) 28*/ 29 30#include "sysdep.h" 31#include "asm-syntax.h" 32 33#define res_ptr a1 34#define s_ptr a0 35#define s_size d6 36#define cnt d4 37 38 TEXT 39ENTRY(__mpn_lshift) 40 41/* Save used registers on the stack. */ 42 moveml R(d2)-R(d6)/R(a2),MEM_PREDEC(sp) 43 44/* Copy the arguments to registers. */ 45 movel MEM_DISP(sp,28),R(res_ptr) 46 movel MEM_DISP(sp,32),R(s_ptr) 47 movel MEM_DISP(sp,36),R(s_size) 48 movel MEM_DISP(sp,40),R(cnt) 49 50 moveql #1,R(d5) 51 cmpl R(d5),R(cnt) 52 bne L(Lnormal) 53 cmpl R(s_ptr),R(res_ptr) 54 bls L(Lspecial) /* jump if s_ptr >= res_ptr */ 55#if (defined (__mc68020__) || defined (__NeXT__) || defined(mc68020)) 56 lea MEM_INDX1(s_ptr,s_size,l,4),R(a2) 57#else /* not mc68020 */ 58 movel R(s_size),R(d0) 59 asll #2,R(d0) 60 lea MEM_INDX(s_ptr,d0,l),R(a2) 61#endif 62 cmpl R(res_ptr),R(a2) 63 bls L(Lspecial) /* jump if res_ptr >= s_ptr + s_size */ 64 65L(Lnormal:) 66 moveql #32,R(d5) 67 subl R(cnt),R(d5) 68 69#if (defined (__mc68020__) || defined (__NeXT__) || defined(mc68020)) 70 lea MEM_INDX1(s_ptr,s_size,l,4),R(s_ptr) 71 lea MEM_INDX1(res_ptr,s_size,l,4),R(res_ptr) 72#else /* not mc68000 */ 73 movel R(s_size),R(d0) 74 asll #2,R(d0) 75 addl R(s_size),R(s_ptr) 76 addl R(s_size),R(res_ptr) 77#endif 78 movel MEM_PREDEC(s_ptr),R(d2) 79 movel R(d2),R(d0) 80 lsrl R(d5),R(d0) /* compute carry limb */ 81 82 lsll R(cnt),R(d2) 83 movel R(d2),R(d1) 84 subql #1,R(s_size) 85 beq L(Lend) 86 lsrl #1,R(s_size) 87 bcs L(L1) 88 subql #1,R(s_size) 89 90L(Loop:) 91 movel MEM_PREDEC(s_ptr),R(d2) 92 movel R(d2),R(d3) 93 lsrl R(d5),R(d3) 94 orl R(d3),R(d1) 95 movel R(d1),MEM_PREDEC(res_ptr) 96 lsll R(cnt),R(d2) 97L(L1:) 98 movel MEM_PREDEC(s_ptr),R(d1) 99 movel R(d1),R(d3) 100 lsrl R(d5),R(d3) 101 orl R(d3),R(d2) 102 movel R(d2),MEM_PREDEC(res_ptr) 103 lsll R(cnt),R(d1) 104 105 dbf R(s_size),L(Loop) 106 subl #0x10000,R(s_size) 107 bcc L(Loop) 108 109L(Lend:) 110 movel R(d1),MEM_PREDEC(res_ptr) /* store least significant limb */ 111 112/* Restore used registers from stack frame. */ 113 moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2) 114 rts 115 116/* We loop from least significant end of the arrays, which is only 117 permissible if the source and destination don't overlap, since the 118 function is documented to work for overlapping source and destination. */ 119 120L(Lspecial:) 121 clrl R(d0) /* initialize carry */ 122 eorw #1,R(s_size) 123 lsrl #1,R(s_size) 124 bcc L(LL1) 125 subql #1,R(s_size) 126 127L(LLoop:) 128 movel MEM_POSTINC(s_ptr),R(d2) 129 addxl R(d2),R(d2) 130 movel R(d2),MEM_POSTINC(res_ptr) 131L(LL1:) 132 movel MEM_POSTINC(s_ptr),R(d2) 133 addxl R(d2),R(d2) 134 movel R(d2),MEM_POSTINC(res_ptr) 135 136 dbf R(s_size),L(LLoop) 137 addxl R(d0),R(d0) /* save cy in lsb */ 138 subl #0x10000,R(s_size) 139 bcs L(LLend) 140 lsrl #1,R(d0) /* restore cy */ 141 bra L(LLoop) 142 143L(LLend:) 144/* Restore used registers from stack frame. */ 145 moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2) 146 rts 147END(__mpn_lshift) 148